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Forensic Science - 02 Crime scene investigation & evidence collection

3.
TRACE EVIDENCE.
Evidence that occurs when different objects contact one another.
Examples include:
 Pet hair on your clothes or carpet.
 Hair on your brush.
 Fingerprints on a glass.
 Soil tracked into your house from your shoes.
 A drop of blood on your clothes.
 A fibre from clothing.
 A used tissue.
Locard’s Exchange principle.
 Whenever two people come in contact with each other a physical
transfer occurs.
 The intensity, duration & nature of the materials in contact
determine the extent of the transfer.

11.
CHAIN OF CUSTODY.
Ensures that the evidence has been responsibly
handled as it was passed from the crime scene to
courtroom.
http://it.toolbox.com/blogs/securitymonkey/of-bags-and-men-chain-of-custody-6679

12.
CASE STUDY 1 – LILLIAN OETTING (1960)
Three Chicago socialites were murdered in Starved Rock State Park, Illinois. All
three women had fractured skulls. Their bodies, bound with twine, were found
in a cave. Near the bodies of the women, a bloodied tree limb was found and
considered to be the murder weapon. Because all three women had been
staying at a nearby lodge, the staff of the lodge was questioned. Chester
Weger, a 21-year-old dishwasher at the lodge, was asked about a blood stain
on his coat. He said it was animal blood. He agreed to take a lie detector test
and passed it. He was requestioned and took a second lie detector test and
passed it as well. The blood was examined by the state crime lab and found
to be animal blood as Weger had indicated at questioning. The case reached
a dead end.
Source:
http://troytaylorbooks.blogspot.com.au/2013/03/the-
starved-rock-murders.html

13.
Investigators decided to revisit the evidence. The
rope used to bind the women was examined
more carefully. It was found to be 20-stranded
twine sold only at Starved Rock State Park.
Identical twine was found in an area accessible
to Weger. He again became a prime suspect.
The blood on his coat was reexamined by the
FBI Crime Lab and found to be human and
compatible with the blood of one of the victims.
Weger submitted to another lie detector test and
failed it. Weger was found guilty for the murder of
one of the women, Lillian Oetting, and has spent
more than 45 years in prison. He recently
petitioned the Governor of Illinois for clemency,
saying he was beaten and tortured into making
the confession. He still maintains his innocence.
CASE STUDY 1 – LILLIAN OETTING (1960)
Source:
http://troytaylorbooks.blogspot.com.au/2013/03/the-
starved-rock-murders.html

14.
CASE STUDY 2 – THE ATLANTA CHILD
MURDERS (1979–1981).
Wayne Williams is thought to be one of the worst
serial killers of adolescents in U.S. history. His
victims were killed and thrown into the
Chattahoochee River in Georgia. Williams was
questioned, because he was seen near where a
body had washed ashore. Two kinds of fiber were
found on the victims. The first kind was an unusual
yellow-green nylon fiber used in floor carpeting.
Through the efforts of the FBI and DuPont
Chemical Company, the carpet manufacturer was
identified. The carpet had been sold in only 10
states, one of them being Alabama, where
Williams lived. Thus, the fibers found on the
victims were linked to carpet fibers found in
Williams’ home.
Source: http://listfave.com/top-10-most-vicious-serial-
killers-of-20th-century/

15.
CASE STUDY 2 – THE ATLANTA CHILD
MURDERS (1979–1981).
Another victim’s body yielded the second type of fiber. This fiber was determined
to be from carpeting found in pre-1973 Chevrolets. It was determined that
only 680 vehicles registered in Alabama had a matching carpet. Williams
owned a 1970 Chevrolet station wagon with matching carpet. The probability
of both types of fibers being owned by the same person was calculated. The
odds against another person owning both carpet types were about 29 million
to one. Williams was convicted and sentenced to two life terms.
Source:
http://dingeengoete.blogspot.com.au/2012/05/this-day-in-
history-may-22-war-of-roses.html

16.
CASE STUDY 3 – JONBENET RAMSEY CASE
(1996).
The 1996 homicide investigation of six-year-old
JonBenet Ramsey provides valuable lessons in
proper crime-scene investigation procedures.
From this case, we learn how important it is to
secure a crime scene. Key forensic evidence
can be lost forever without a secure crime
scene.
In the Ramsey case, the police in Boulder,
Colorado, allowed extensive contamination of
the crime scene. Police first thought JonBenet
had been kidnapped because of a ransom note
found by her mother. For this reason, the police
did not search the house until seven hours after
the family called 911. The first-responding police
officer was investigating the report of the
kidnapping. The officer did not think to open the
basement door, and so did not discover the
murdered body of the girl.
Source: http://www.babble.com/mom/jonbenet-ramseys-
dad-regrets-letting-her-do-beauty-pageants/

17.
CASE STUDY 3 – JONBENET RAMSEY CASE
(1996).
Believing the crime was a kidnapping, the police blocked off JonBenet’s bedroom
with yellow and black crime-scene tape to preserve evidence her kidnapper
may have left behind. But they did not seal off the rest of the house, which
was also part of the crime scene. Then the victim’s father, John Ramsey,
discovered his daughter’s body in the basement of the home. He covered her
body with a blanket and carried her to the living room. In doing so, he
contaminated the crime scene and may have disturbed evidence. That
evidence might have identified the killer.
Once the body was found, family, friends, and police officers remained close by.
The Ramseys and visitors were allowed to move freely around the house.
One friend even helped clean the kitchen, wiping down the counters with a
spray cleaner—possibly wiping away evidence. Many hours passed before
police blocked off the basement room. A pathologist did not examine the body
until more than 18 hours after the crime took place.
Officers at this crime scene obviously made serious mistakes that may have
resulted in the contamination or destruction of evidence. To this day, the crime
remains unsolved.

18.
CASE STUDY 3 – JONBENET RAMSEY CASE
(1996).
1. What mistakes were made by the
Boulder Police Department in
securing the crime scene?
2. What specific kinds of evidence
may have been compromised?
3. What could the police have done
differently to secure the crime
scene and the evidence?
Source:
http://www.thesun.co.uk/sol/homepage/news/1403896/Pa
rents-of-child-beauty-queen-JonBenet-cleared.html